Far-UVC light: A new tool to control the spread of airborne-mediated microbial diseases

David Welch; Manuela Buonanno; Veljko Grilj; Igor Shuryak; Connor Crickmore; Alan W. Bigelow; Gerhard Randers-Pehrson; Gary W. Johnson; David J. Brenner

Virus inactivation. Fig. 1 shows representative fluorescent 40x images of mammalian epithelial cells 50 incubated with airborne viruses that had been exposed in aerosolized form to far-UVC doses (0, 0.8, 1.3 51 or 2.0 mJ/cm 2 ) generated by filtered 222-nm excimer lamps. Blue fluorescence was used to identify the 52 total number of cells in a particular field of view, while green fluorescence indicated the integration of 53 live influenza A (H1N1) viruses into the cells. Results from the zero-dose control studies (Fig. 1 Fig. 2 shows the surviving fraction, as a function of the incident 222-nm far-UVC dose, of 57 exposed H1N1 aerosolized viruses, as measured by the number of focus forming units in incubated 58 epithelial cells relative to unexposed controls. Linear regressions (see below) showed that the survival 59 results followed a classical exponential UV disinfection model with rate constant k=1.8 cm 2 /mJ (95% 60 confidence intervals 1.5-2.1 cm 2 /mJ). The overall model fit was good, with a coefficient of 61 determination, R 2 = 0.95, which suggests that most of the variability in virus survival was explained by 62 the exponential model. The rate constant of 1.8 cm 2 /mJ corresponds to an inactivation cross-section 63 (dose required to kill 95% of the exposed viruses) of D95 = 1.6 mJ/cm 2 (95% confidence intervals 1.4-1.9 64 mJ/cm 2 ).